Electronic control systems for such installations offer many different possibilities for the regulation of the various parameters which affect conditions inside the vehicle, such that the comfort of the users is very significantly improved. With the aid of a device such as a keypad, the users are able to define directly the various elements of the conditions they require for the atmosphere in the cabin, in particular the temperature of the air which is distributed by the installation into the cabin of the vehicle and the pattern of distribution of this air.
The Applicant has however observed that it is desirable to improve the comfort of the users even more, in certain respects. In this connection, when for example a motorist reaches a toll station, the window has to be opened in order for money to change hands. Opening of the window changes the atmospheric conditions within the cabin, and in prior art installations of the above kind, the regulation (adjustments) of the various conditions of the cabin, effected by the installation, tends to over-compensate for the change that results from opening of the window. This over-compensation is far from helpful, having regard to the relative shortness of the time for which the window is open.
In addition, an occupant of a vehicle will generally decide to open the window or the sunroof, and leave it open for a prolonged period, because he knows that by doing so, he will be more comfortable. However, when that happens, the control system of the ventilation or air conditioning installation will then tend to seek a way to compensate exactly for the effects of opening the window or roof. In addition, the operations of making adjustments are accompanied by mechanical actions, which, in spite of the improvements achieved up to the present time, still make themselves evident to the occupants to the vehicle, in terms of variations in airflow and temperature which accompany them, and also in terms of various noises.